As some of you know I build japanese performance cars (and the occasional domestic and foreign) and just got into the DIY projector stuff, so my appologies for any mistakes i make in technical terms.
I was walking around the junkyard looking for a MAF for a turbo silvia motor for a customer when out of the corner of my eye I caught sight of a lens. When I pulled the trash off of the thing I was holding a pretty large (about the length of a regulation football) housing which turned out to adjust in length. It has 4 points that are used for mouinting it with screws to another peice which I do not have. So when I took all the screws out of the adjustment holes it became two peices
Peice one has a lexan bottom and behind it is a half circle dome lens butted up to it. this distance is not adjustable. This is the larger cylindrical housing and peice two slides into it.
Peice two is a cylinder with a thick lens, shorter convex side closest to half dome lens of peice one and longer convex side away from it. About 8 inches from this is a larger lens, flat size closest to longer side of thick lens and convex side out, this distance is also not adjustable. Peice two resembles a telescope lens.
Just guessing the first peice, with the flat lexan and dome lense are about 8 inches in diameter. The lenses in peice two are about 8 inches from each other, the thick lens is about 6 inches in diameter and the other lense with the flat side in and convex side out is about 8 inches in diameter (matches the dome and flat lenses of the other peice)
The only focal length adjustment is between the dome and the thick lens by sliding peice two in and out of peice one. This makes the object viewed through the end fill up more or less of the view and magnifies the object.
So looking at some completed projectors the largest I saw was a 80mm lens from a copier and all the lenses used for focusing the light onto the wall or screen were built into a tube and seemed to have the same diameter, my questions are
1) Is this lens to large for a projector application
2) Is the fact that the thicker convex lens is smaller than the final flat backed convex lense going to cause a problem such as distorted edges.
3) I noticed that the peice with the flat lexan lens and the dome in it do not flip images but seem to give it a fish eye effect and make objects smaller and farther away but very clean and crisp but will it be used in this project? I have not heard mention of anything other than a two lens tube used to focus by adjustment of focal length and a condensor used from the light source into the frenel and then off of a cold and/or uv mirror into the tube with the two lenses.
4) Can this dome lens be used a condensor or is the fact that it is circular going to cause dimness in the edges (more so than normal) or distortion in those edges?
I cleaned up the inside and outside of the housing as well as the lenses which have no damage on them other than a small burn on the flat lexan external side of peice one which I am replacing with a new peice tomorrow. Researching the only name on the peices, Delta IV made by US Precision Lens I found out it is a 3m company which makes lenses for big companies like Xerox, Mitsumi, Mitsubisi etc etc. Anyone know what this was from and if I can not use it does anyone want to trade for condensors, fresnels, smaller lense and halide lights systems for my diy projector project?
I was walking around the junkyard looking for a MAF for a turbo silvia motor for a customer when out of the corner of my eye I caught sight of a lens. When I pulled the trash off of the thing I was holding a pretty large (about the length of a regulation football) housing which turned out to adjust in length. It has 4 points that are used for mouinting it with screws to another peice which I do not have. So when I took all the screws out of the adjustment holes it became two peices
Peice one has a lexan bottom and behind it is a half circle dome lens butted up to it. this distance is not adjustable. This is the larger cylindrical housing and peice two slides into it.
Peice two is a cylinder with a thick lens, shorter convex side closest to half dome lens of peice one and longer convex side away from it. About 8 inches from this is a larger lens, flat size closest to longer side of thick lens and convex side out, this distance is also not adjustable. Peice two resembles a telescope lens.
Just guessing the first peice, with the flat lexan and dome lense are about 8 inches in diameter. The lenses in peice two are about 8 inches from each other, the thick lens is about 6 inches in diameter and the other lense with the flat side in and convex side out is about 8 inches in diameter (matches the dome and flat lenses of the other peice)
The only focal length adjustment is between the dome and the thick lens by sliding peice two in and out of peice one. This makes the object viewed through the end fill up more or less of the view and magnifies the object.
So looking at some completed projectors the largest I saw was a 80mm lens from a copier and all the lenses used for focusing the light onto the wall or screen were built into a tube and seemed to have the same diameter, my questions are
1) Is this lens to large for a projector application
2) Is the fact that the thicker convex lens is smaller than the final flat backed convex lense going to cause a problem such as distorted edges.
3) I noticed that the peice with the flat lexan lens and the dome in it do not flip images but seem to give it a fish eye effect and make objects smaller and farther away but very clean and crisp but will it be used in this project? I have not heard mention of anything other than a two lens tube used to focus by adjustment of focal length and a condensor used from the light source into the frenel and then off of a cold and/or uv mirror into the tube with the two lenses.
4) Can this dome lens be used a condensor or is the fact that it is circular going to cause dimness in the edges (more so than normal) or distortion in those edges?
I cleaned up the inside and outside of the housing as well as the lenses which have no damage on them other than a small burn on the flat lexan external side of peice one which I am replacing with a new peice tomorrow. Researching the only name on the peices, Delta IV made by US Precision Lens I found out it is a 3m company which makes lenses for big companies like Xerox, Mitsumi, Mitsubisi etc etc. Anyone know what this was from and if I can not use it does anyone want to trade for condensors, fresnels, smaller lense and halide lights systems for my diy projector project?
That is exactly what it is. So what would be the best lay out to use this as you said the screen has to be right up against the lens. Does this mean i do not need the condensor/fresnel/uv/cold mirror set up and just use a lcd with a light source shinning through?
I am going to google crt projector as soon as I post this so that I can get some more knowledge on the subject. Thanks alot for the response
I am going to google crt projector as soon as I post this so that I can get some more knowledge on the subject. Thanks alot for the response
Ok from what I have gathered this is one of the 3 lenses used in a CRT (cathode ray tube) projector which uses red/blue/green grouping to make a picture much the same way a normal television does. So what I need to do is get some object (presumably a lcd monitor of 5" or so) to do the work of mixing the red/blue/green in a matrix, get enough light through it as to be able to travel through space and onto a surface.
As you said the 5" has to be up against the lense, I suppose I would need to take the low level back lighting off of a 5" lcd, and use a HID, high power halogen or a halide bulb bulb with a chamber for ample cooling as not to distort the liquid crystals, shine it through and adjust the focal length by moving the housings in and out of each other?
As you said the 5" has to be up against the lense, I suppose I would need to take the low level back lighting off of a 5" lcd, and use a HID, high power halogen or a halide bulb bulb with a chamber for ample cooling as not to distort the liquid crystals, shine it through and adjust the focal length by moving the housings in and out of each other?
answer found through search technology
http://www.diyaudio.com/forums/sear...d=209724&sortby=lastpost&sortorder=descending
for anyone else who wants to find it
http://www.diyaudio.com/forums/sear...d=209724&sortby=lastpost&sortorder=descending
for anyone else who wants to find it
- Status
- Not open for further replies.